In the 17th century, Louis XIV’s military engineer Vauban enlarged existing defences and built news ones in order to protect the trading port of La Rochelle and the new arsenal at Rochefort. Soon a line of defences stood guard over the entrance to the Charente river – Fort Vauban at Fouras and Fort Louvois at Bourcefranc-le-Chapus, Fort de la Rade on the Ile d’Aix and Fort Lupin on the banks of the Charente.

Other fortifications include the imposing citadel at St-Martin-de-Ré, which is still in use today, and the town’s star-shaped ramparts. Vauban also remodelled the modest fishing harbour into a port capable of taking military ships, and today St-Martin is one of 12 key Vauban sites awarded World Heritage Site status by UNESCO.

Further fortification work continued well into the 19th century, one of the most impressive examples being Fort Boyard, a stone fortress between Ile d’Aix and Ile d’Oléron that rises out of the waves like a stone ship. Begun under Napoleon I and finished in 1857 under Napoleon III, it eventually became a prison and is now best known as the location for a world famous television game show. See Fort Boyard from the lofty ramparts of the citadel in Château-d’Oléron or from the deck of a passing cruise boat.

Back on the mainland, the salt marshes behind the coastal town of Brouage led to its success as a salt port. Visit the 17th century citadel, the historic Victuals Hall, and the birthplace of Samuel de Champlain, founder of Québec in 1608.